Enclosures

ABSTRACT

The invention concerns enclosures having especial application in relation to storing equipment liable to atmospheric deterioration comprising a rigid base having a strip peripherally secured thereto with coupling means sealingly to connect the strip to a bag-like cover to provide a generally weather proof enclosure.

,lan. 8, 1974 United States Patent 1191 Boucher ENCLOSURES 2,731,0551/1956 Smith 52/2 3,009,540 11/1961 165/7 x [75] Invent Bouche" Mlnsted,3,088,619 5/1963 Boucher........................ 150/52 R x nearS1ttmgbourne, England 3,103,083 9/1963 2,752,928 7/1956 Seeger.......Barker.... [7.3] Asslgnee' E; g ':fg 3,500,593 3 1970 Kwake.... gan3,241,269 3/1966 Reffell........,...... 22 Filed; 3 1972 3,557,515[/1971 MacCracken.....

[2l] Appl. No.1 223,234

Primary ExaminerMeyer Perlin Assistant Examiner-Ronald C. Capossela [30]Forelgn Apphcatwn Pnomy Data Attorney- Parmelee, Miller, Welsh & KratzFeb. 10, 1971 ABSTRACT The invention concerns enclosures having especialapplication in relation to storing equipment liable to atmosphericdeterioration comprising a rigid base hav- 2 N2 2 f 3 M6 13 m2 "2 Mb c.r "a e S m d Ld hr. .1] 00 55 98/33 R; 150/52 R; ing a stripperipherally secured thereto with coupling [56] 1 References Cited meanssealingly to connect the strip to a bag-like cover to provide agenerally weather proof enclosure. UNITED STATES PATENTS 3,626,83612/1971 Schneidler '6 Claims, 9 Drawing Figures PATENTEDJAN 8 1974 SHEET2 OF 6 PATENTED JAN 8 I974 SHEET 5 OF 6 ENCLOSURES This inventionrelates to enclosures having especial application as protectivecontainers for heavy equipment such as land and water vehicles, aircraftor the like, stores and provisions and any equipment and spares thereforwhich are prone to deterioration. The invention relates also to systemsincluding an array of such containers or enclosures arranged and adaptedfor convenient supervision.

In certain applications, especially for example, in the military fieldit is necessary to store large quantities of valuable equipment, e.g.,large numbers of vehicles spares for vehicles and other equipment overlongperiods of time, without substantial deterioration occurring even inthe absence of regular servicing of the equipment and yet in such afashion that such equipment can be brought into service rapidly at shortnotice.

If no protection from corrosion and deterioration through atmosphericconditions is given to vehicles and the like it is necessary to servicethem very regularly to maintain them in good condition. Obviously, wherelarge numbers of vehicles are concerned this involves considerableeffort on behalf of numerous very skilled personnel and thus greatexpense.

Whilst some degree of protection from damp and consequent deteriorationthrough corrosion etc., can be given by storing the vehicles and otherequipment in buildings or huts of a prefabricated, but of generallypermanent, nature, economic considerations as well as considerations ofspace dictate that a single such building should house a large number ofvehicles and equipment.

If air conditioning is to be employed to maintain a low level ofrelative humidity in the buildings more economic use can be made of theair conditioning plant if as few buildings as is possible are used tohouse a maximum number of vehicles and large quantities of equipment.Unfortunately where a large number of vehicles and/or equipment isstored in a single building it may not be possible in an emergency tobring all of the vehicles and equipment into use as quickly as isdesired.

Furthermore a building or but within which a large number of vehiclesand/or equipment is accommodated (in close proximity) makes aconveniently large and valuable target for an enemy in the event ofenemy action and still further may well present a serious fire hazard innormal conditions.

According to one aspect of the present invention there is provided anenclosure comprising a permanent rigid base formed in a manner as todiscourage water vapour transmission; a strip of flexible sheet materialof low water vapour transmissibility extending around the periphery ofsaid base; first means sealingly attaching said strip to said base; acover of generally open baglike form formed of flexible sheet materialof low water transmissibility having a mouth; connecting means aboutsaid mouth; and co-operating connecting means on said strip sealingly toconnect said .strip to said cover.

According to another aspect of the present invention there is providedan enclosure for an article comprising: a permanently formed groundsecured rigid base formed in a manner as to discourage water vapourtransmission; a peripheral recess extending around said base; a strip offlexible sheet plastics material of low water vapour transmissibilityhaving one longitudinal edge portion sealingly secured to the base; onehalf of a sliding clasp fastener extending along of other longitudinaledge portion of the strip; a cover of open-bag like form formed offlexible sheet plastics material of low water vapour transmissibilityhaving a mouth, a second half of said sliding clasp fastener extendingabout the edge portion of the cover constituting said mouth andsealingly, but releasably, connected to the fastener half on said strip;said base recess being dimensioned to house said strip when such stripis not connected to said cover to provide protection for the strip whenthe article isplaced on, or removed from, the base; the arrangementbeing such that when the sliding clasp fastener halves areinterconnected a substantially hermetically sealed enclosure is providedand an enviroment may be maintained within the enclosure having a lowerrelative humidity than the ambient air outside the enclosure and yetpermits for ready removal of the article from the enclosure.

According to yet another aspect of the present invention there isprovided an installation comprising a plurality of enclosures asreferred to hereinbefore.

According to a still further aspect of the present invention there isprovided an air-supported or inflated enclosure comprising: a rigidbase; a peripheral recess extending around the base; a strip of flexiblesubstantially water and air impermeable plastics material having onelongitudinal edge portion secured to-the base; a cover of open bag-likeform formed of a substantially water and air impermeable flexibleplastics sheet material having a mouth; complementary halves of asliding clasp fastener being secured respectively to a secondlongitudinal edge of the strip and about the edge portion of the mouthof the cover to permit the strip and the cover to be sealingly butreleasably interconnected to form an enclosure; and an inlet and anoutlet in said enclosure, each of generally frusto-conical form andbeing formed of a flexible material.

It is desirable to provide a plurality of particular base and coversizes so that broadly a modular system is created and in this waypermitting mass production of the components and thus minimising theproduction of special one-off covers. I

In order that the invention may be more readily understood and furtherfeatures of the same more readily appreciated, various embodiments ofenclosure in accordance with the invention will now be described (aswill certain ancillary equipment used with such enclosures) by way ofexample with reference to the accompanying drawings in which:

FIG. I is a diagrammatic vertical sectional view of a typical embodimentof enclosure; FIG. 1A is an enlarged fragmentary sectional view showingthe form of a sliding clasp fastener used to couple two portions of theenclosure sealingly but releasably together;

FIG. 2 is a fragmentary enlarged sectional view show ing a peripheraledge portion of a base of the enclosure with a strip provided forconnection to a cover shown coiled in a stowed condition;

FIG. 3 is a view very similar to FIG. 2 showing an alternativearrangement of base with strip;

FIG. 4 is a generally diagrammatic and schematic view of an installationshowing a series of enclosures in different conditions of assembly andshowing diagrammatically various items of ancillary equipment and also ahumidity monitoring arrangement;

FIG. is a part-elevation, part-vertical sectional view through ageneration desiccator used as ancillary equipment in enclosuresaccording to this invention;

FIG. 6 is an exploded, part-diagrammatic, perspective view of aframe-arrested recirculatory regeneratable dehumidifier also used asancillary equipment with the enclosures in accordance with thisinvention;

FIG. 7 is a part diagrammatic perspective view, partially cut away, of ahousing suitable for a helicopter the helicopter being omitted for thesake of clarity; and

FIG. 8 is a part diagrammatic side elevational view of a furtherembodiment of enclosure suitable for use as a workshop and comprising anair supported/inflated enclosure, such view showing ancillary equipmentused with such enclosure.

In one embodiment of enclosure for storing vehicles the enclosurecomprises a base comprising a seal formed by a sheet of plasticsmaterial 1 which has a low water vapour transmissibility being laid onthe ground 2, and superimposed by a layer of concrete 3 which forms arigid, substantially permanent, platform or base. The layer of concreteis edged with channel section girders 4 (of a metal or of a plasticsmaterial), the sides 5, 6 of the channel extending in the same plane asthe upper and lower surfaces of the platform and the channel 7 definedthereby being open outwardly. Sealingly secured within the channel isone longitudinal edge portion of a strip 8 of sheet (for exampleplastics) material which extends around the base 3. The freelongitudinal edge of said strip is provided with one of thecomplementary parts 9 of a sliding clasp fastener such as described inUS. Pat. No. 3,088,619 and which is shown in FIG. 1A.

The remainder of the enclosure is defined by a cover 10 in the form of abag having an open mouth, the peripheral edge of the bag defining suchmouth being provided with the other complementary part 11 of theaforementioned sliding clasp fastener.

When the enclosure is not in use and is bereft of its cover 10 the basehas said flexible strip 8 rolled back and accommodated within thechannel 7 all around the base, so that the strip 8 is protected when avehicle or equipment is moved onto, or from the base 3. FIG. 2 showsthis arrangement.

In use, after for example a vehicle such as a tank or lorry has beendriven onto the base 8 (the vehicle lying entirely within the boundaryof the base 8) the vehicle is covered with said cover 10, said strip 8is unrolled from said channel 7 and the complementary parts or halves 9,1 1 of the sliding clasp fastener are secured together using a slidingclasp in known fashion.

If desired in an alternative arrangement the channel sectioned girdersmay have sides which lie within and at right angles to the plane of thebase. This embodiment is shown in FIG. 3 and the channel section girdersare designated 20, the sides 21, 22 and the channel defined therebetween23; the seal being designated 24.

A complete system or installation may comprise a plurality of such bases3 laid in appropriate arrangements such as, for example, rows, part ofan installation being shown in FIG. 4 of the accompanying drawings. Whenthe enclosures have been filled with vehicles and equipment and havebeen sealed the air contained within the enclosures is dehumidified aswill be described hereinafter.

However in an installation many, if not all, the enclosures would eachcontain a relative humidity senser diagrammatically shown and designated25 electrically connected by wires 26 which pass sealingly through thecovers and these wires 26 are connected to a terminal 27, and byrespective further conductors 28 (only diagrammatically shown) to amonitoring station 29 common to a plurality of containers at which pointone or more indicators reading the information provided by the sensers25 are provided.

It will be appreciated that any suitable relative humidity senser may beutilised. One form of senser may comprise a sodium chloride impregnatedlength of ribbon which changes its electrical resistance in response tochanges in humidity.

After closing an enclosure the relative humidity therein is initiallyreduced to an acceptable safe level by the use of a dehumidifier whichmay take any suitable form, for example, a replaceable static (butregeneratable) desiccator 30 (shown in FIG. 5 in detail) located in theenclosure or by means of a transportable or permanent recirculatingdehumidifier 31 (shown in FIG. 6 in detail). Such a dehumidifier may beelectrically powered and may be connected to a source of electricity viaan electrical socket located in, or adjacent said enclosure.

After a certain storage period at an acceptable relative humidity level,increase in such relative humidity above an accepted level (the increasebeing due to some water vapour transference through the enclosure) willbe indicated at the common monitoring station 29 and when the humiditywithin any of the enclosures rises above the predetermined acceptablelevel, the appropriate indicator registers this fact (either on arelative humidity-calibrated dial or by means of a visual or an auralalarm or otherwise) and the person responsible for such stored equipmentcan take appropriate action, which may either be to replace thedesiccator 30 within the appropriate enclosure or which may alternatelybe to activate the dehumidifier 31.

The dehumidifiers and desiccators may taken a variety of forms butsuitable types will be briefly described hereinafter.

Still further, while each enclosure may be provided with its ownpermanent dehumidifying device located therewithin, the enclosure mayalternatively be provided with an inlet 32 and outlet 33 (both sealablewhen not required) connectable by hoses 34, 35 to a portabledehumidifier 36.

One embodiment of regeneratable desiccator 30 will now be describedbriefly. In this embodiment the desiccator comprises a cylindrical drum40 constituting a body, closable when being stored and unused sealinglyby a lid 41, the drum 40 being divided into two compartments by aperforated divider 42, a first lower compartment 43 housing heatingmeans in the form of a fan heater 44 whereas the second uppercompartment 45 houses a plurality of cages 46. Each cage has perforatedtop and bottom walls 47, 48 retained in spaced parallelism by a flangeon a cylindrical side wall 49, the side wall 49 of each case having arib 50 to space its cage from the internal surface of the drum 40.Pelletised silica gel forms the desiccant and is provided in each cage,the pellets being designated 51.

To assist transportation of the drum 40, for example when removing from,or introducing into, an enclosure such desiccator, a handle 52 isprovided.

The system adopted when using a desiccator of this type is first toensure that the desiccant is active by energising the heater 44 with thelid 41 removed to drive moisture from the desiccant and then to seal thedesiccator completely. The desiccant is then transported and placed inan enclosure to be dehumidified and the lid 4lll removed and then theenclosure is sealed. When the desiccant becomes saturated the desiccatoris removed from the enclosure and replaced by yet another suchdesiccator, the desiccator which has been removed'then having itsdesiccant regenerated.

One embodiment of dehumidifier which could be used is described andclaimed in our US. Pat. No. 3,594,990. However because vapours in theenclosures may well be inflamable or explosive the dehumidifierpreferably includes flame arrest means.

A flame arrest dehumidifier will now be briefly de scribed by way ofexplanation.

The dehumidifier comprises a body 611 having an inlet chamber 62 and anoutlet chamber 63 separated by a partition 64. The inlet chamber 62houses an electric fan 5 (not shown), and the outlet chamber 63 houses acombined heating and desiccating core 63a comprising a wire heatingelement wrapped in a desic cant carrying material.

A pair of opposed inlet ports 65 are connected by lengths of conduit 66,67 respectively to a control valve unit 68, which serves to connect oneor other of such inlet ports to the inlet chamber 63. Similarly, a pairof outlet ports 69, are connected by lengths of conduit 70, 71,respectively to a second control valve unit 72 which serves to connectone or other of the outlet ports to the outlet chamber 63.

One boundary of the outlet chamber 63 is constituted by an end wall 73that is provided with a large aperture 74 therein. Equally spaced aroundthe aperture 74 and extending outwardly of the end wall 73 are fourstuds that are threaded at their ends remote from the end wall 73.The'studs carry a circular valve plate 75 (constituting a valve member)that consists of a circular member having a radius greater than that ofthe aperture 74, the circular member being provided with four aperturedsemi-circular lugs for slidable association with the studs. Arectangular retaining plate 76 serves to limit the distance along whichthe valve plate 75 may.

be moved on the studs. There is provided on each stud a helicalcompression spring 77 positioned between, and engaging with, the valveplate 75 and the retaining plate 76, and acting to bias the valve plate75 towards a closed position against the end wall 73 of the outletchamber 63. A silicone rubber seal is provided between the valve plateand the end wall 73 so that the plate will satisfactorily seal theaperture 76. The retaining plate 76 is provided with a valve platearresting spring 73.

The end plate 73 is also provided with a rectangular aperture 79 whichcommunicates with a volume within the interior of the body 611 of thedehumidifier and which lies above the outlet chamber 63. Both theaperture 74 and the aperture 79 are provided with baffles made of aflame resistant or flame arresting material such as chromised nickelRETIMET (Trade Mark) referenced 80 and 81 respectively. Both of thebaffles 80, 31 are connected to the end wall 73 in such a manner thatall gasses and/or vapours passing through the apertures 74, 79 must passthrough the baffles. Appropriate retaining plates are provided to retainthe aforementioned components in their operative positions. Althoughonly one end of the body 61 has been described and illustrated it is tobe understood that the opposite end of the body is as has been describedhereinbefore.

The inlet port 65 is constituted by a short length of pipe that leads toa cuboid housing 82 mounted on the side of the body 61 of thedehumidifier. Contained within the housing 82 there is a baffle 83 offlame resistant material such as, for example, said chromised nickelRETIMET (Trade Mark) which entirely fills the housing. A length ofconduit serves to connect the side of the housing remote from the port65 to the control valve unit 68. Mounted on the conduit 9 there is asafety switch 84 which is sensitive to temperature or pressure and whichwill operate when the temperature or the pressure of gas and/or vapourwithin the conduit exceeds a certain predetermined value. Such a switchmight, for example, include a bimetallic strip of a thermistor in whichcases the switch will be sensitive to heat. Alternatively the switch maybe any suitable switch that is sensitive to pressure. The switch isconnected in a circuit which controls said electric fan in the inletchamber 62. g

The structure of each of the inlet and outlet ports of the dehumidifierare similar to that of the inlet port 65 and consequently they will notbe individually described in this specification.

Said electric fan may be of any suitable form and typically an axialflow fan may be utilised. The electrical fan is housed within a specialhousing which in turn is located within the inlet chamber 62. Thisspecial housing has an inlet aperture which is provided with a bafi'leof flame resistant material and which is retained in position by theretaining plate. Again the baffle may be made of any suitable flameresistant material such as chromised nickel RETIMET (Trade Mark).

Mounted within the body 61 is a control box 35 which contains theelectrical equipment necessary to control the electric fan and thecontrol valve units 66, 69.

It will be apparent from the foregoing description that there are foursafety switches 66 contained within the body ll, one for each inlet andoutlet. The switches 34 are all connected in series between one electricpower supply terminal and the electric fan so that if any of theseswitches is in the open circuit" condition the electric fan will berendered inoperative.

in forming the dehumidifier thus far described the body and all theassociated parts are very rigidly constructed, parts being weldedtogether wherever practicable, in order to minimise the damage that maybe caused to the equipment should an explosion occur therein. Thedehumidifier is, in this particular embodiment a portable unit.

When it is desired to dehumidify the contents of an enclosure it ismerely necessary to couple an inlet port (for example, the port 65) andan outlet port (for example the port 69) of the dehumidifier to theenclosure inlet and outlet by for example the flexible pipes 34, 35.

Assuming that the pipes are so coupled to the container and assumingthat the valve control units 68, 72 are in a suitable condition,energisation of the electric 'fan will result in the air and/or vapourwithin the container being drawn into the inlet port 65 and forcedthrough the housing 62 and the baffle 83 contained therein and into theinlet chamber 62. The gas and/0r vapour will then pass to the fan andthe fan will serve to propel the gas and/or vapour through an aperturein the partition 64 into the outlet chamber 63, where it will passthrough said core. As the gas and/or vapour passes through the core itwill come into intimate contact with the desiccant which is carried bythe core, and water vapour contained within the gas and/or vapour willbe absorbed by the desiccant. After passing over the desiccant the gasand/or vapour will then pass through the control valve unit 72 andthence to the outlet port 69. As the output port 69 is connected to theenclosure by the pipe 35, the gas and/or vapour extracted from theenclosure through the pipe 34 connected to the inlet port 65 of thedehumidifier is eventually returned to the container. This cycle ofoperation could be continued either until the humidity within theenclosure has dropped to desired level or until the desiccant ceases tobe effective.

Once the desiccant has become ineffective (or at least only partiallyeffective) the desiccant is regenerated by circulating air through theunconnected inlet and outlet ports with the core being heated so thatwater vapour is driven from the desiccant and is carried away anddischarged through the unconnected outlet.

When the moisture has been driven from the desiccant the heating currentis ceased and the valve contained within the control valve units arereturned to their original condition, so that a dehumidifying cycle canbe continued as and when desired.

When utilising the dehumidifier of the invention to dehumidify acontainer having an atmosphere of a gas and/or vapour mixture thatcontains explosive constituents there is a remote possibility that anexplosion may occur within the dehumidifying unit with the result thatthere may be a subsequent fire within the body of the dehumidifier whichmight pass into the enclosure being dehumidified. In the event of anexplosion within the inlet chamber 62 or the outlet chamber 63 thepressure within the chamber will rapidly rise and consequently .thepressure being exerted upon the valve plate 75 will also rise to such anextent that the valve plate 75 will be urged away from the end wall 73.Gas under pressure will then escape through the aperture 74, therebyrelieving the excess pressure present within the cavity. The gas and/orvapour that escapes through the aperture 74 must pass through the baffle80 of flame resistant material, and consequently should there be a firepresent within the body of the dehumidifier the flames willnot passthrough the baffle 80. However, should the fan still be propelling gasand/or vapour mixture into the chamber it is conceivable for any firepresent within the chamber to continue thereby warming the baffle 80.Eventually the baffle 80 could reach such a temperature that it nolonger has flame arresting properties, and consequently flames couldpass through the bafile. However, the dehumidifier is provided with saidsafety switches (such as that designated 84) situated in the conduitsleading to each of the inlet ports and each of the outlet ports whichserve to render the electric fan inoperative as soon as the temperatureand/or pressure within the conduits rises above a certain predeterminedlevel. Consequently, if there were an explosion or a fire within thebody of the dehumidifier, one or more of the safety switches 84 will betriggered and the fan will be made inoperative.

Each of the inlet ports and each of the outlet ports of the dehumidifieras stated hereinbefore is provided with a housing containing a baffle offlame resistant material so that should an explosion or a fire occurwithin the dehumidifier the flames will not be transmitted to the gasand/or vapour contained within the container which is beingdehumidified.

Where the disadvantages of the use of huts and like permanent housingare not so prevalent the bases of the various enclosures may be formedwith the floor of the building and each individual base is defined by aboundary formed by an upwardly open channel in the floor surface, thebase and channel conveniently lined with moisture sealing material andwith one longitudinal edge of said strip 8 sealingly secured to thechannel.

Where tracked vehicles such as tanks are to be located in the base apair of rigid elongate supports at the spacing of the tracks of thevehicles, may be laid over the base.

Another embodiment, which would be used for helicopters differs fromthat used for vehicles of a general type as described hereinbefore. Inthis embodiment the enclosure is profiled suitably as shown in FIG. 7 ofthe accompanying drawings and is provided with means to encouragecirculation of the enviroment within the enclosure. This circulation isdesirable as it has been noted that in certain shaped enclosures (suchas this type) particular portions are prone to become excessively humidas compared with the general overall level of humidity in-the enclosure.

For the sake of clarity in FIG. 7, showing a helicopter enclosure, thehelicopter has been omitted.

In this enclosure, which is designated 90, a fan blower 91 isdiagrammatically shown having an inlet 92 and outlet 93 each providedwith flame arrest material (as described in relation to thedehumidifier). The blower contains a tangential flow fan 91a and aheating element 91b of any desired form.

Connected to the outlet 93 of the blower 91 is a length of tubing 94formed from a strip of a plastics material folded along its length andwelded to itself to provide the tube 93 with an integral flange 95 whichis secured, for example by welding, to the interior surface of theenclosure 90. The tube may be perforated at intervals therealong. Theblower 91 is connected to a source of electricity by means of anelectrical lead 96. This system for providing circulation of theenviroment within the enclosure is only necessary, or desirable, inenclosures of particular shapes.

The preferred material for the covers and the boundary strips in theembodiments described hereinbefore is plasticised polyvinylchloridesheeting, of various grades. preferably reinforced, for example, withterylene cloth. Antistatic additives may also be included. Polyethylenefilm may also be applied to the sheeting in certain applications forextra resistance to certain oils.

In order to protect this sheeting from wind stresses (which might resultin tearing or stretching) it is preferred, after an enclosure has beensealed, to cover the cover with a relatively heavy net designated 97,which is thereafter secured at its edges in any desired manner aroundthe boundary of the base.

It will be evident that the enclosure and system/installation providedby the present invention provide a means by which considerable costs maybe saved in storing equipment by rendering unnecessary the constructionof permanent or semi-permanent buildings for storage, and by reducingconsiderably the amount of preventitive maintenance which wouldotherwise have to be carried out. In addition it will be seen that thestored equipment can be brought into service extremely quickly andwithout undue effort.

The aforementioned enclosures described by way of example are allparticularly suitable for housing one or more articles but as has beenexplained hereinbefore the invention also has application in relation toair supported or inflated enclosures which, whilst they could housearticles, would nevertheless normally be used as workshops andmaintenance rooms.

Thus in a further embodiment an enclosure suitable for a workshopcomprises a rigid base 101, a peripheral recess extending around thebase in the form of a metal channel 102 to which is connected onelongitudinal edge portion of a flexible strip of material 103 formed ofa substantially water and air impermeable plastics material, theopposite longitudinal edge portion of the strip 103 carrying one half ofa sliding clasp fastener which is adapted to be sealingly connected to acomplementary half of the fastener which is secured around the mouth ofa cover 104 of generally open bag-like form. This cover 104 is providedwith a slit which con stitutes a doorway and this slit is sealinglyclosable by a similar sliding clasp fastener 105.

Oppositeend portions of the cover 104 have respectively an inlet and anoutlet.

The inlet comprises a circular aperture around which is located a collar108to which is secured a frustoconical sleeve or tube 106 also formed ofa flexible plastics material, such cone being arranged to protrudeeither to the interior of the cover or to protrude to the exteriorthereto. This conical inlet is provided for connection to a'blowerlocated either outside or within the enclosure and such blower isdesignated 107, the

blower being shown in dotted lines in the interior of the enclosure andin full lines at the exterior of the enclosure merely by way ofillustration that two alternative locations are available. Peripheralsealing means are provided around the collar 108 these sealing meansbeing adapted to co-operate with complementary sealing means on aclosure cap 109.

The outlet which is also a circular aperture in the wall of the cover104 is provided with a'collar identical to the collar 108, the outletcollar being designated 110 to which is connected a frusto-conicalhollow sleeve 111 identical to the sleeve 106.

Again a closure cap equivalent to the cap 109 is provided for closingthe outlet, this cap being designated 112 and having sealing means forco-operation with the collar 110.

As both inlet and outlets and their associated sleeves 106 and 111 areidentical it will be understood that their roles may, when required, bereversed.

Placed over the cover 104 is a netting which is provided with anappropriate closable opening to permit access to be gained to thesealable access slit in the side of the cover 104, the opening in thenet being designated 113 and the net itself being designated 114.

The nature of the material, which is conveniently plasticisedpolyvinylchloride (reinforced as and when the exterior air pressure theconical sleeve 11] will droop (as shown in dotted lines) effectivelysubstantially closing the outletso that unnecessary egress of any airbeing introduced into the cover by the blower 107 positioned at theinlet is avoided. The arrangement however is such that as the airpressure increases within the cover the frusto-conical sleeve 111becomes erect and permits air to escape at a sufficiently high rate toprovide a desirable exchange of air within the cover but not atva ratewhich would permit the cover to collapse at least when the blower isoperative.

The slit normally sealed by the clasp fastener is arranged so that whenopened to permit entry of a person into the cover, immediate deflationof the cover does not occur, any sudden drop in differential pressurebetween the exterior and the interior of the enclosure resulting in theoutlet sleeve 111 drooping and at least partly closing.

The blower may of course include filters or be associated with filters,dehumidifiers, air conditioners and items such as heaters 107a so thatthe precise air conditions within the cover may be maintained. As andwhen desired the inlet and the outlet may be closed by the caps 109,112.

I claim:

1. An enclosure for an article comprising:

a permanently formed ground secured rigid base formed in a manner as todiscourage water vapour transmission;

a peripheral recess extending around a portion of said base; I

a strip of flexible sheet plastics material of low water vapourtransmissibility having one longitudinal edge portion sealing secured tothe base;

one half of a sliding clasp fastener extending along the otherlongitudinal edge portion of the strip;

a cover of open bag-like form formed of flexible sheet plastics materialof low water vapour transmissibility having a mouth;

a second half of said sliding clasp fastener extending about the edgeportion. of the cover constituting said mouth and sealingly, butreleasably, connected to the fastener half on said strip;

said base recess being dimensioned to house the portion of said stripadjacent said peripheral recess when such strip is disconnected fromsaid cover to provide protection for that portion of the strip when thearticle is placed on, or removed from, the base;

the arrangement being such that when the sliding clasp fastener halvesare interconnected a substantially hermetically sealed enclosure isprovided and an environment may be maintained within the enclosurehaving a lower relative humidity than the ambient air outside theenclosure and yet permits for ready removal of the article from theenclosure.

2. An enclosure according to claim 1, wherein humidity sensing means areprovided within the enclosure.

3. An enclosure according to claim 2, wherein said sensing means areconnected to an electrical lead extending from the exterior of theenclosure.

4. An air-supported or inflated enclosure comprising:

a rigid base;

a peripheral recess extending around the base;

a strip of flexible substantially water and air impermeable plasticsmaterial having one longitudinal edge portion secured to the base;

a cover of open bag-like form formed of a substantially water and airimpermeable flexible plastics sheet material having a mouth;

complementary halves of a sliding clasp fastener being securedrespectively to a second longitudinal edge of the strip and about theedge portion of the mouth of the cover to permit the strip and the coverto be sealingly but releasably interconnected to form an enclosure;

an inlet and an outlet in said enclosure, each of generallyfrusto-conical form and being formed of a flexible material; and

means connected to said inlet for inflating said enclosure.

5. An enclosure according to claim 4, wherein said flexible conicaloutlet changes configuration to discourage egress of air therethroughwhen the pressure differential between the interior and the exterior ofthe enclosure drops below a predetermined value.

6. An enclosure according to claim 5, wherein a sub-

1. An enclosure for an article comprising: a permanently formed groundsecured rigid base formed in a manner as to discourage water vapourtransmission; a peripheral recess extending around a portion of saidbase; a strip of flexible sheet plastics material of low water vapourtransmissibility having one longitudinal edge portion sealing secured tothe base; one half of a sliding clasp fastener extending along the otherlongitudinal edge portion of the strip; a cover of open bag-like formformed of flexible sheet plastics material of low water vapourtransmissibility having a mouth; a second half of said sliding claspfastener extending about the edge portion of the cover constituting saidmouth and sealingly, but releasably, connected to the fastener half onsaid strip; said base recess being dimensioned to house the portion ofsaid strip adjacent said peripheral recess when such strip isdisconnected from said cover to provide protection for that portion ofthe strip when the article is placed on, or removed from, the base; thearrangement being such that when the sliding clasp fastener halves areinterconnected a substantially hermetically sealed enclosure is providedand an environment may be maintained within the enclosure having a lowerrelative humidity than the ambient air outside the enclosure and yetpermits for ready removal of the article from the enclosure.
 2. Anenclosure according to claim 1, wherein humidity sensing means areprovided within the enclosure.
 3. An enclosure according to claim 2,wherein said sensing means are connected to an electrical lead extendingfrom the exterior of the enclosure.
 4. An air-supported or inflatedenclosure comprising: a rigid base; a peripheral recess extending aroundthe base; a strip of flexible substantially water and air impermeableplastics material having one longitudinal edge portion secured to thebase; a cover of open bag-like form formed of a substantially water andair impermeable flexible plastics sheet material having a mouth;complementary halves of a sliding clasp fastener being securedrespectively to a second longitudinal edge of the strip and about theedge portion of the mouth of the cover to permit the strip and the coverto be sealingly but releasably interconnected to form an enclosure; aninlet and an outlet in said enclosure, each of generally frusto-conicalform and being formed of a flexible material; and means connected tosaid inlet for inflating saiD enclosure.
 5. An enclosure according toclaim 4, wherein said flexible conical outlet changes configuration todiscourage egress of air therethrough when the pressure differentialbetween the interior and the exterior of the enclosure drops below apredetermined value.
 6. An enclosure according to claim 5, wherein asubstantially rigid collar extends about said inlet and said outlet andclosure caps are provided to permit sealing of the enclosure byengagement thereof with said collars.